How big can the gray bird can produce eggs

The gray bird can be sexually mature in half a year, but it will not be able to breed after eight months.It usually built the nest in the shrub or small trees, and it can breed after the nest is built.Every year, 4 nests can be reproduced. There are 4-7 eggs per nest. Usually it will only be incubated for 16-18 days to get out of the shell. It will open your eyes for 10 days.Generally, 45 days will leave the mother bird.